Traditionally, beer has been brewed from just barley malt, hops and water. However, often part of the barley malt is substituted with adjuncts such as corn, rice, sorghum, and wheat, refined starch or readily fermentable carbohydrates such as sugar or syrups. Adjuncts are used mainly because they are readily available and provide carbohydrates at a lower cost than is available from barley malt. Other advantages may also be achieved, e.g. enhanced physical stability, superior chill-proof qualities, and greater brilliancy.
Mashing is the process of converting starch from the milled barley malt and adjuncts into fermentable and unfermentable sugars to produce wort of the desired composition. Traditional mashing involves mixing milled barley malt and adjuncts with water at a set temperature and volume to continue the biochemical changes initiated during the malting process. The mashing process is conducted over a period of time at various temperatures in order to activate the endogenous enzymes responsible for the degradation of proteins and carbohydrates. However, rice and corn starch which are often used as adjunct starch have a higher gelatinization temperature than the malt starch. Therefore, such adjuncts are cooked and gelatinized in a separate “cereal cooker” before being added to the malt mash. Thus, while the use of adjunct reduces the costs of raw material price it requires an additional investment in the cereal cooker as well as an additional cost for energy for heating the adjunct. A more simple mashing process allowing use of ungelatinized adjunct grist is thus desirable.